There is a need in animal husbandry for methods of improving the utilization of food. It is important not only that the growth of the animals be promoted but that the utilization of the food be directed in a different way, namely, to produce less fat and more protein. Some compounds have been described which enhance the utilization of food and change the carcass composition in some species of food livestock. Baker et al. have described (Fed. Proc. 42 No. 4 p. 816, No. 3 p. 668) that a compound called clenbuterol functions in this way. However, while this may be the best such agent published in the scientific literature, clenbuterol is not as active as other compounds in poultry, sheep or swine, especially compared to the compounds used in this invention.